title: Characterization of Ile-His-Arg-Phe, a novel rice-derived vasorelaxing peptide with hypotensive and anorexigenic activities.
abstract: METHODS
  Recently, we found that dipeptide Arg-Phe (RF) had cholecystokinin (CCK)-dependent vasorelaxing activity. The RF sequence is often observed in the primary structure of natural food proteins. In the current study, we investigated enzymatic conditions for the release of RF-related peptides from rice glutelin, a major storage protein, using gastrointestinal proteases. RF-related peptides were then characterized.
  
  
  RESULTS
  It was found that RF and Ile-His-Arg-Phe (IHRF) were released in the chymotrypsin digest of the partial structure of rice glutelin. We then focused on previously unidentified IHRF, corresponding to rice glutelin(155-158). IHRF had vasorelaxing activity in the mesenteric artery of spontaneous hypertensive rats (SHRs). Orally administered IHRF lowered systolic blood pressure in SHRs. The antihypertensive activity of IHRF was more potent and long-lasting than that of RF. IHRF-induced vasorelaxing activity was not blocked by inhibitors of nitric oxide synthase and cyclooxygenase, but by an antagonist for CCK₁ receptor. IHRF also had CCK-like suppressive activities in food intake and gastrointestinal transit. IHRF increased intracellular Ca²⁺ flux and CCK release in the enteroendocrine cell STC-1.
  
  
  CONCLUSIONS
  IHRF, a novel CCK-dependent vasorelaxing peptide, decreases both blood pressure and food intake in rodents.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho Uji, Kyoto, Japan.
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Kontani
authors.forename: Ryo
authors.initials: R
authors.lastname: Omae
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kagebayashi
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kaneko
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamada
authors.forename: Takafumi
authors.initials: T
authors.lastname: Mizushige
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Kanamoto
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohinata
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001067:Appetite Depressants / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002766:Cholecystokinin / Q000494:pharmacology; D019858:Enteroendocrine Cells / Q000187:drug effects / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000201:enzymology; D005983:Glutens / Q000737:chemistry; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D012275:Oryza / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D001067:Appetite Depressants; D010455:Peptides; D014665:Vasodilator Agents; D005983:Glutens; D002766:Cholecystokinin; D019001:Nitric Oxide Synthase; D011451:Prostaglandin-Endoperoxide Synthases; D010447:Peptide Hydrolases
keywords: Blood pressure; Cholecystokinin; Food intake; Rice; Vasorelaxation